6.6-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki rafael.j.wysocki@intel.com
[ Upstream commit b38aa87f67931e23ebc32c0ca00a86dfa4688719 ]
In order to avoid running __thermal_zone_device_update() for thermal zones going away, the thermal zone lock is held around device_del() in thermal_zone_device_unregister() and thermal_zone_device_update() passes the given thermal zone device to device_is_registered(). This allows thermal_zone_device_update() to skip the __thermal_zone_device_update() if device_del() has already run for the thermal zone at hand.
However, instead of looking at driver core internals, the thermal subsystem may as well rely on its own data structures for this purpose. Namely, if the thermal zone is not present in thermal_tz_list, it can be regarded as unavailable, which in fact is already the case in thermal_zone_device_unregister(). Accordingly, the device_is_registered() check in thermal_zone_device_update() can be replaced with checking whether or not the node list_head in struct thermal_zone_device is empty, in which case it is not there in thermal_tz_list.
To make this work, though, it is necessary to initialize tz->node in thermal_zone_device_register_with_trips() before registering the thermal zone device and it needs to be added to thermal_tz_list and deleted from it under its zone lock.
After the above modifications, the zone lock does not need to be held around device_del() in thermal_zone_device_unregister() any more.
Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Reviewed-and-tested-by: Lukasz Luba lukasz.luba@arm.com Acked-by: Daniel Lezcano daniel.lezcano@linaro.org Stable-dep-of: 827a07525c09 ("thermal: core: Free tzp copy along with the thermal zone") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/thermal/thermal_core.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c index 5a9068e8f050d..69b89a71f44eb 100644 --- a/drivers/thermal/thermal_core.c +++ b/drivers/thermal/thermal_core.c @@ -487,11 +487,16 @@ int thermal_zone_device_is_enabled(struct thermal_zone_device *tz) return tz->mode == THERMAL_DEVICE_ENABLED; }
+static bool thermal_zone_is_present(struct thermal_zone_device *tz) +{ + return !list_empty(&tz->node); +} + void thermal_zone_device_update(struct thermal_zone_device *tz, enum thermal_notify_event event) { mutex_lock(&tz->lock); - if (device_is_registered(&tz->device)) + if (thermal_zone_is_present(tz)) __thermal_zone_device_update(tz, event); mutex_unlock(&tz->lock); } @@ -1292,6 +1297,7 @@ thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *t }
INIT_LIST_HEAD(&tz->thermal_instances); + INIT_LIST_HEAD(&tz->node); ida_init(&tz->ida); mutex_init(&tz->lock); init_completion(&tz->removal); @@ -1365,7 +1371,9 @@ thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *t }
mutex_lock(&thermal_list_lock); + mutex_lock(&tz->lock); list_add_tail(&tz->node, &thermal_tz_list); + mutex_unlock(&tz->lock); mutex_unlock(&thermal_list_lock);
/* Bind cooling devices for this zone */ @@ -1455,7 +1463,10 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz) mutex_unlock(&thermal_list_lock); return; } + + mutex_lock(&tz->lock); list_del(&tz->node); + mutex_unlock(&tz->lock);
/* Unbind all cdevs associated with 'this' thermal zone */ list_for_each_entry(cdev, &thermal_cdev_list, node) @@ -1472,9 +1483,7 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz) ida_free(&thermal_tz_ida, tz->id); ida_destroy(&tz->ida);
- mutex_lock(&tz->lock); device_del(&tz->device); - mutex_unlock(&tz->lock);
kfree(tz->tzp);